Solve for $x$ and $y$ using substitution. ${-x+3y = 10}$ ${x = -4y+11}$
Explanation: Since $x$ has already been solved for, substitute $-4y+11$ for $x$ in the first equation. ${-}{(-4y+11)}{+ 3y = 10}$ Simplify and solve for $y$ $4y-11 + 3y = 10$ $7y-11 = 10$ $7y-11{+11} = 10{+11}$ $7y = 21$ $\dfrac{7y}{{7}} = \dfrac{21}{{7}}$ ${y = 3}$ Now that you know ${y = 3}$ , plug it back into $\thinspace {x = -4y+11}\thinspace$ to find $x$ ${x = -4}{(3)}{ + 11}$ $x = -12 + 11$ ${x = -1}$ You can also plug ${y = 3}$ into $\thinspace {-x+3y = 10}\thinspace$ and get the same answer for $x$ : ${-x + 3}{(3)}{= 10}$ ${x = -1}$